Effect of pharmacological doses of niacin on testicular structure and function in normal and diabetic rats

The potential prophylactic and therapeutic impacts of niacin on ischemia/reperfusion injury of testis

INTRODUCTION

The testicular ischemia-reperfusion (I/R) injury is characterized by the excessive aggregation of un-scavenged reactive oxygen species, leading to the heightened levels of oxidative stress. This phenomenon plays a pivotal role in the pathophysiology of testicular torsion damage.

OBJECTIVE

The current study aimed to detect the prophylactic and therapeutic effects of niacin on testicular I/R injury.

STUDY DESIGN

Twenty-four healthy adult male Sprague Dawley rats were randomly allocated into three groups as follows: (1) sham group, (2) torsion/detorsion (T/D) group, and (3) treatment group which received 200 mg/kg niacin along with testicular T/D. Torsion/detorsion was induced by 2 h of torsion followed by 10 days of reperfusion period. In the treatment group, niacin was injected 30 min before the reperfusion period intraperitoneally and continued for 10 days by oral gavage.

RESULTS

T/D was associated with marked decreases in terms of sperm count, viability, and kinematic parameters versus the sham group (P < 0.05), which niacin significantly reverted the kinematic parameters (P < 0.05). I/R injury caused a significant increase in the number of abnormal epididymal sperms compared to the sham group (P < 0.05). Niacin decreased the epididymal sperm abnormality significantly compared to the T/D group (P < 0.05). Tissue abnormalities in T/D group, such as edema, hyperemia, inflammation, and necrosis were completely visible histopathologically, while the histological changes in the niacin-treated group were better than those in the T/D group. Regarding the pathological parametric evaluations, I/R injury significantly reduced the mean testicular biopsy score (MTBS), germinal epithelial cell thickness (GECT), and mean seminiferous tubular diameter (MSTD), and increased the tubular hypoplasia/atrophy (THA) compared to the sham group (P < 0.05), which niacin treatment significantly improved the MTBS and GECT compared to the T/D group (P < 0.05). T/D significantly increased the oxidative stress index (OSI) and lipid peroxidation (MDA) (P < 0.05). Niacin significantly reduced the OSI and MDA levels compared to the T/D group (P < 0.05).

DISCUSSION

The current study found that niacin has preventive/therapeutic effects against the elevation of oxidative stress markers and depletion of antioxidants during I/R injury. Following administration of niacin, a reduction in histologic injury was observed in rats. In our study, we showed the antioxidant properties of niacin and its capacity to protect against I/R damage.

CONCLUSION

The findings of the present investigation revealed that niacin, as an antioxidant agent, can suppress the oxidative stress induced by testicular I/R injury, and can be used as a supplementary agent in the treatment of those undergoing testicular torsion surgery.

Morin hydrate ameliorates heat-induced testicular impairment in a mouse model

BACKGROUND

Heat stress is known to adversely affect testicular activity and manifest the pathogenesis of spermatogenesis. Morin hydrate is a plant-derived compound, which contains a wide range of biological activities. Thus, it is hypothesized that morin hydrate might have an ameliorative effect on heat-induced testicular impairment. There has not been any research on the impact of morin hydrate on heat-induced testicular damage.

METHODS

The experimental mice were divided into four groups, groups1 as the normal control group (CN), and the second which underwent heat stress (HS) by immersing the lower body for 15 min in a thermostatically controlled water bath kept at 43 °C (HS), and third and fourth heat-stressed followed by two different dosages of morin hydrate 10 mg/kg (HSM10) and 100 mg/kg (HSM100) for 14 days.

RESULTS

Morin hydrate treatment at 10 mg/kg improved, circulating testosterone levels (increases 3βHSD), and oxidative stress along with improvement in the testis and caput and corpus epididymis histoarchitecture, however, both doses of morin hydrate improved sperm parameters. Morin hydrate treatment significantly increases germ cell proliferation, (GCNA, BrdU staining), expression of Bcl2 and decreases expression of active caspase 3. Heat stress also decreased the expression of AR, ER- α, and ER-β, and Morin hydrate treatment increased the expression of these markers in the 10 mg/kg treatment group.

CONCLUSION

Morin hydrate ameliorates heat-induced testicular impairment modulating testosterone synthesis, germ cell proliferation, and oxidative stress. These effects could be manifested by regulating androgen and estrogen receptors. However, the two doses showed differential effects of some parameters, which requires further investigations.

Beyond the surface: Consequences of methyl tert-butyl ether (MTBE) exposure on oxidative stress, haematology, genotoxicity, and histopathology in rainbow trout

Concerns have been raised about the possible environmental effects of methyl tert-butyl ether (MTBE), which is widely used as a gasoline additive. This research aimed to look at the consequences of MTBE contamination on rainbow trout (Oncorhynchus mykiss), emphasizing oxidative stress, genotoxicity, and histopathological damage. After determining the LC50-96 h value, the effects of sub-lethal doses of MTBE (0 (control), 90, 180, and 450 ppm) on rainbow trout were investigated. In fish tissues, the levels of oxidative stress indicators such as malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. The comet assay, which measures DNA damage in erythrocytes, was used to determine genotoxicity. Histopathological examinations were done on liver and gill tissues to examine potential structural anomalies. The results of this study show that MTBE exposure caused considerable alterations in rainbow trout. Increased oxidative stress was demonstrated by elevated MDA levels and decreased SOD activity, while the comet assay revealed dose-dependent DNA damage, implying genotoxic effects. Histopathological study revealed liver and gill tissue abnormalities, including cell degeneration, necrosis, and inflammation. Overall, this research highlights the possible sub-lethal effects of MTBE contamination on rainbow trout, stressing the need of resolving this issue. Future research should look at the impacts of chronic MTBE exposure and the possibility of bioaccumulation in fish populations.

Effects of pharmacological doses of niacin on subacute glucocorticoid-induced testicular damage in rats

Glucocorticoid excess adversely affects male reproduction. This study evaluates effects of pharmacological doses of niacin on testicular structure and function in dexamethasone-treated rats. Adult rats (48) were randomly assigned to 6 equal groups: (1) Negative control (NC): normal rats; (2) Positive control (PC): dexamethasone at 7 mg/kg/day by intraperitoneal injections for 7 days; groups 3-6 (N50, N100, N200, and N400): dexamethasone and concomitant treatment with niacin at 50, 100, 200, and 400 mg/kg/day by oral gavages. Testicular weight and volume of PC rats were significantly lower than the NC group (p < .05). Testicular volume of rats in the N50 and N200 groups was statistically similar to the NC group. Significant decreases in serum testosterone with a slight LH increase were detected in the PC group. Nacin at 50 mg/kg reversed serum testosterone to NC levels and increased serum LH concentration. Niacin only slightly increased epididymal spermatozoa number while all groups of niacin-treated rats had significantly higher percentages of motile spermatozoa compared with the PC group. Hypospermatogenesis, germ cell degeneration and depletion, epithelial vacuolization, and degenerated Leydig cells were observed in PC rats. Lesions were relatively milder in niacin-treated rats. Johnsen scores were also significantly higher in niacin-treated rats. Niacin reduced apoptosis as shown by TUNEL assay. In conclusion, niacin administration at pharmacological doses dose-dependently ameliorates the destructive effects of dexamethasone on sperm motility, Johnsen score, and testicular cell apoptosis in rats with the latter can be considered a decisive mechanism for its positive effects on testis.

Effects of Leptin antagonist treatments on testosterone and testis histological characteristics of immature male mice

The present study aimed to ascertain how leptin antagonist injection affected testis weights, testis morphology and testosterone levels in immature male Swiss mice. Animals were administered with anti-leptin antibody subcutaneously, with or without equine chorionic gonadotropin (eCG). Control animals were treated with non-immune serum. Blood and testis were collected. The Androgen profile was analyzed in serum and tissue homogenates, and testes were histologically examined. Compared to controls, mice treated with an anti-leptin antibody with or without gonadotropins had a significant (p<0.05) increase in testis weight. Testosterone concentrations in the testis were significantly (p<0.05) higher in mice administered with anti-leptin antibody compared to control, but testosterone concentrations in blood were not affected. The diameter of seminiferous tubules, the diameter of the lumen and the width of spermatogenic cells were significantly (p<0.05) higher in mice in treatment groups compared to controls. We conclude that anti-leptin antibody administration in immature male mice increased testosterone concentrations in the testis and improved testis histological characteristics. Keywords: leptin; mouse; histology; testis; testosterone; immature male

Evaluation of a single dose of intra-testicular insulin treatment in heat-stressed mice model

Insulin plays important role in testicular functions such as germ cell proliferation and steroidogenesis, despite its conventional role as a hypoglycaemic agent. It is also well known that testicular activity is severely get affected by heat stress and heat stress induces testicular pathogenesis. The effect of insulin on heat-induced testicular impairment has not been investigated. Thus, it is hypothesized that insulin might modulate testicular activity in a heat-stressed model. Experimental mice were separated into 4 groups; the first group was the normal control (CN), and the second group was subjected to heat stress (HS) by submerging the lower body part in a thermostatically controlled water bath maintained at 43°C for 15 min. The third and fourth groups were treated with a single dose of intra-testicular insulin (0.6 IU/mice) before and after heat stress. Animal tissue samples were collected after 14 days of heat treatment. Insulin treatment did not improve the sperm parameters; however, both insulin pre and post-treatment improved the markers of spermatogenesis such as Johnsen score, germinal epithelium height and the number of stages VII/VIII. The histoarchitecture of testis also showed amelioration from heat-induced pathogenesis in the insulin-treated groups. Insulin treatment has also increased the proliferation of germ cells (increased PCNA and GCN), survival (Bcl2), and decreased apoptosis (active caspase-3). Furthermore, insulin treatment decreased MDA levels, without pronounced effects on the activities of antioxidant enzymes. Heat stress also decreased the circulating testosterone and oestrogen levels, and insulin treatment significantly increased oestrogen levels only. Although testosterone showed an increasing trend, it was insignificant. The expression of aromatase, AR, ER-α, and ER-β was down regulated by heat-stress and insulin treatment up regulated these markers. In conclusion, our results showed the amelioration of heat-induced testicular impairment by pre and post-intra-testicular insulin treatments. Insulin-associated improvements in the pre-and post-treatment groups suggested a preventive mechanism of insulin against heat stress in the testis.

Dietary Fibre Supplementation Improves Semen Production by Increasing Leydig Cells and Testosterone Synthesis in a Growing Boar Model

Testicular development is imperative to spermatogenesis, and pre-puberty is the key period for testis development. This study, therefore, investigated the effects of fibre supplementation on testis development and its possible mechanism in a growing boar model. Thirty Yorkshire boars were randomly divided into a control group (Control) and a fibre group (Fibre) from day 0 to 90 after weaning, with three pigs per pen and five pens per treatment. Blood and testes were collected for analysis. Dietary fibre supplementation had no significant effect on growth performance, testicular volume, or libido but increased the semen production of boars. Boars fed with fibre had lower serum cholesterol (CHO) and low-density lipoprotein (LDL) levels compared to those on the Control diet; however, testicular CHO, triglyceride (TG), and LDL concentration in the Fibre group were significantly higher than the Control group (P &lt; 0.01). Testicular histological analysis showed that seminiferous tubules and testicular germ cells of 120-day-old boars were densely arranged in the Fibre group, and the number of Leydig cells was significantly higher than that of the Control group (P &lt; 0.001). Furthermore, the diet supplemented with fibre significantly decreased leptin, leptin receptor (Leptor), and luteinising hormone (LH) concentrations in boar serum (P &lt; 0.05), whereas follicle-stimulating hormone (FSH) and testosterone concentrations were significantly increased (P &lt; 0.05). Meanwhile, the expression of AMH, AMHR2, and SYCP3 genes related to proliferation and differentiation, and hormone-related genes STAR and SOCS3, were significantly up-regulated (P &lt; 0.05). OCCLUDIN expression was up-regulated, whereas CDH2 expression was down-regulated. In conclusion, increased fibre intake during the pre-puberty period in growing boar is crucial for Leydig cell proliferation, up-regulating the expression of genes related to hormone synthesis and thereby promoting the secretion of testosterone and semen production.

Reproductive Effects of Nicotinamide on Testicular Function and Structure in Old Male Rats: Oxidative, Apoptotic, Hormonal, and Morphological Analyses

Aging is a natural process in which morphological and functional abnormalities in living organisms increase irreversibly. Nicotinamide (NAM) acts both as a precursor of many metabolites and as a cofactor of many enzymes involved in cell energy metabolism, homeostasis of redox balance, and regulation of signaling pathways. In this study, we investigated the effects of NAM treatment on morphological and biochemical changes in testis of old rats. The rats were treated with 200, 400, and 800 mg/kg NAM doses as a gavage for 1 month. As a result, we determined the dose-dependent therapeutic effects of NAM on testicular tissues of aged rats. We found that NAM treatment decreased total oxidant status (TOS), caspase 3 (CASP3) and cytochrome c (CYC) levels and increased total antioxidant status (TAS), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels (P<0.05). NAM treatment significantly reduced the age-related histopathological parameters such as cellular loss, necrotic tissue, interstitial edema, tubular damage, and vascular congestion in aged rat testicular tissue compared to the control group. Moreover, based on histomorphological analysis, we detected that NAM treatment resulted in a dose-dependent improvement in testicular tissue damage of old rats. Consequently, the results showed that the reproductive decline caused by aging could be ameliorated with NAM treatment.